The use of cutting or scoring balloons for angioplasty and other procedures is well documented. Typically, such balloons are made of a thin but strong material, Pebax being one example, which is able to be wrapped into a very small diameter and yet which is strong when inflated. Cutting or scoring balloons typically have one or more cutting or scoring elements provided on or in the balloon wall which extend beyond the perimeter of the balloon wall in a radially outward direction. These cutting or scoring elements may be formed of a stiff material, even of metal, which is attached to the balloon, for instance by bonding or adhesion. In other embodiments, the cutting or scoring elements may be formed integrally with the balloon wall, and they may be made of different material from that of the remainder of the balloon.
As a result of the structure and materials used for such scoring balloons, they are not particularly suited for traditional angiographic imaging techniques, particularly ultrasonic imaging, thereby having to rely upon less advantageous CRT and MRI imaging. Specifically, such balloons tend to be very difficult to see and in some instances can be virtually invisible. In order to mitigate these disadvantages, such balloons can be inflated with a contrast media which is opaque under ultrasonic imaging. However, suitable contrast media does not resolve the imaging difficulties when the balloon is in its deflated condition. Moreover, contrast media tends to be relatively more viscous than other fluids which can be used to inflate such balloons, with the result that the time required for inflation and deflation of a balloon with contrast media is increased. The increased viscosity also limits the minimum diameter of the inflation and deflation lumen and therefore the minimum achievable diameter of the balloon catheter.
Balloon catheters suitable for imaging are disclosed, for example, in US-2005/0222596, U.S. Pat. No. 5,507,292, U.S. Pat. No. 5,429,136 and U.S. Pat. No. 5,383,460.